1. Field of the Invention
The present invention relates to a camera having a magnetic head arranged to record and/or reproduce various magnetic signals in or from a magnetic layer provided on a film.
2. Description of Related Art
In Japanese Laid-Open Patent Application No. HEI 4-68329, there is disclosed a camera, which is arranged to record magnetic signals at film frames used for photographing (hereinafter referred to as exposed frames) with a magnetic head and to find the leading part of unexposed frame portions of the film by discriminating exposed frames from unexposed ones according to the presence or absence of the magnetic signals in a case where the camera is loaded again after the cartridge of the film is taken out before all frames are used for photographing. In Japanese Laid-Open Patent Application No. HEI 5-158165, there is disclosed a camera, which is arranged to retract a magnetic head from a film surface when it is not necessary to reproduce magnetic signals recorded on the film. In Japanese Laid-Open Patent Application No. HEI 5-183236, there is disclosed a camera, which is arranged to reproduce magnetic signals from a film in rewinding the film for the purpose of checking data recorded in winding the film.
Further, in Japanese Laid-Open Patent Application No. HEI 6-155526, there is disclosed a camera, which is arranged to write magnetic signals for all frames at the time of rewinding the film instead of recording magnetic signals every time one frame is wound after taking a shot.
Among these cameras of the prior art mentioned above, the camera arranged to perform magnetic recording for all frames at the time of rewinding the film has presented a problem as follows. In a case where the camera is loaded with a film cartridge containing a film already exposed in part, i.e., a partially exposed film, magnetic information might be recorded again, in rewinding the film, for exposed frames at which magnetic information has already been recorded.
Further, each of the cameras either arranged to record magnetic information (signals) at the time of film rewinding or arranged to record magnetic information every time a shot is taken for one frame necessitates an action of finding and fetching, to the aperture part of the camera, a frame which is in a leading position among unexposed frames when the camera is loaded with a film cartridge containing a partially exposed film. The frame fetching action is carried out by detecting magnetic information provided at each frame and by finding frames having no record of magnetic information. In this instance, the process of detecting the magnetic information is performed in moving one frame portion of the film currently located at the aperture position to an extent of one frame amount of the film. Therefore, when the leading (first) frame among the unexposed frames is found to have no record of magnetic information, a frame located next to the leading unexposed frame is already in the aperture position. The film, therefore, must be moved back by one frame amount when the first unexposed frame is found. Meanwhile, since the film counter of the camera is arranged to show the number of frames forwarded by incrementing its count by one every time one frame amount of the film is forwarded (transported), a frame number on display is larger by one than the frame number of the leading (first) unexposed frame with which a photographing operation is to be actually allowed to begin. This state of display is confusing to the operator of the camera.
Further, in the case of the camera of the type performing magnetic recording for all frames at the time of film rewinding, the magnetic head may be brought into pressed contact with the film only at the time of film rewinding by some switching means, which can be simply arranged to bring the magnetic head into contact with the film and to move it away from the film. However, if the camera is loaded with a film cartridge containing a partially exposed film, it becomes necessary to bring the magnetic head into contact with the film in search of the leading unexposed frame as mentioned above. To meet this requirement, the sequence of actions of the camera must be arranged to bring the camera once into a state of film rewinding and, after that, to bring it back into its normal sequence of actions in the above-stated case.